You saved the wrong thing. Salvage refers to saving to the boat and its cargo. Rescuing the
captain get's you a thanks and maybe a
beer. Salvage get's you a reward determined by Admiralty Court rulings that are sometimes centuries old.
If you had taken the
captain ashore and then returned and tied your dinghy to the boat and waited for high tide, you might indeed have been able to negotiate a salvage reward from the boat's
insurance company -- 15%-30% of the boat's value is not out of the question. You would have claimed that there was a chance the
weather would deteriorate or that it would have struck a rock upon re-floating, or a wake might have flooded her while on her side.
Both TowBoatUS and SeaTow are most definitely in the salvage business and carry salvage contracts ready for signing (although a signed
contract is not required). One tow boat mate once told me that "towing pays the bills but salvage makes the profit". The TowBoatUS salvage page specifically says that "stranding" is treated as salvage rather than a free tow -
http://www.boatus.com/towing/salvage-p7.asp
In this case, the tow boat's
draft prevented them from rescuing the boat, you could argue that you deserved the salvage
award.
Here's a fairly long but interesting piece by a lawyer
Salvage Claims Under Admiralty Law | Award for Salvaging a Ship | Lawfirms.com
And here's a picture of a tanker salvage. Seems worth a good fee even if it only is towing
: Ship Photos
Carl